Method for employing ear corn in the manufacture of ethanol

ABSTRACT

Ear corn is picked from corn fields by ear corn harvesters and transported to a central shelling station associated with an ethanol manufacturing facility. Shelled corn from the central shelling station is processed into ethanol at the ethanol manufacturing facility, and corn cobs from the central shelling station are burned to provide process heat for the ethanol manufacturing process. Energy is conserved and costs are reduced during the picking and shelling of the ear corn and by the burning of cobs for process heat.

RELATED APPLICATION

This is a continuation of application Ser. No. 11/623,146, filed Jan.15, 2007, the contents of which are hereby incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates generally to the manufacture of ethanolfrom corn and more particularly to the conservation of fuel andreduction of costs during the ethanol manufacturing process and duringthe harvesting and shelling of the corn.

BACKGROUND OF THE INVENTION

Ethanol is blended with gasoline for use as a fuel in vehicles withinternal combustion engines. A blend containing 10% ethanol as anadditive produces a cleaner burning gasoline. A blend containing 85%ethanol is used as a substitute for gasoline.

Ethanol can be manufactured from a number of domestically grownvegetative materials including corn, sugar cane and sugar beets. Themanufacture of ethanol from domestically grown crops reduces thereliance on imported petroleum as a source for fuel for internalcombustion engines. Corn is the largest domestically grown crop fromwhich ethanol is manufactured.

Corn in a farm field is conventionally harvested by a combine, aself-propelled piece of equipment which picks the ears of corn from thecorn stalks, separates the corn kernels from the corn cobs (shelling)and from the husks on the ears of corn, and returns the cobs and husksto the farm field. The shelled corn is temporarily stored in the combineand then transferred to a vehicle that transports the shelled corn to astorage facility. The cobs and husks that have been returned to the farmfield, together with the stalks and leaves left on the field, arecollectively known as stover, a material which beneficially helps tobuild soil and prevent erosion when left in the field.

Combines came into widespread use for harvesting corn in the latter halfof the twentieth century. Prior to that, corn was hand picked, or it waspicked by a mechanical corn picker that was mounted on or towed by atractor and that was capable of picking, e.g., one to two rows in asingle pass. After the ear corn was picked, it typically was stored onthe farm and then shelled by shelling equipment typically mounted on atruck which traveled to the farm and shelled the ear corn on site. Thecombine replaced both the mechanical picker and the traveling sheller.

Ethanol is made from shelled corn. A multi-stage process is employed toproduce ethanol from shelled corn, and some of these stages require heatsupplied by the combustion of fuel, typically natural gas. Natural gasis also consumed (a) during the production of nitrogen fertilizerapplied to the farm field where the corn is grown and (b) to a lesserextent, during the production of pesticides used on the corn.

Petroleum-based fuels power the vehicles used in the growing andharvesting of corn and in the transporting of corn between the farmfields and the ethanol manufacturing facility.

A drawback to conventional processes for producing ethanol from cornresides in the consumption of large quantities of energy during theethanol manufacturing process and during the growing, harvesting andtransporting of the corn. As noted above, this energy is consumed inlarge part by the combustion of natural gas and of petroleum-basedvehicle fuel. When ethanol from corn is produced at a processing plantdedicated exclusively to the production of ethanol, the ratio of (a) theenergy available from the ethanol to (b) the energy equivalent of thetotal fossil fuel input is 1.77. (Total fossil fuel input comprises bothnatural gas and petroleum-based vehicle fuel.)

The amount of energy consumed during (i) the conversion of corn toethanol, at the ethanol manufacturing facility, is about twice theenergy consumed in (ii) corn production, which includes the manufactureof fertilizer and pesticides with natural gas, as well as the operationof the farming equipment with petroleum-based fuel. Items (i) and (ii)above together constitute at least 90% of the total energy consumed. Theremainder (less than 10%) is consumed in transporting the shelled cornto the ethanol manufacturing facility and in the post-productiondistribution of the ethanol by truck, rail and the like.

Attempts have been made to conserve the natural gas consumed during theethanol manufacturing process by replacing the natural gas with arenewable fuel. In one such instance, the fuel was cattle manure from amassive cattle feeding lot next to which the ethanol manufacturingfacility was located to eliminate the cost of transporting the manurewhich could otherwise be a prohibitive expense. There are, however, onlya limited number of locations where this type of operation can beemployed.

A residual product of the ethanol manufacturing process is a mash knownas “stillage” which is dried and sold as animal feed. The dried stillageis also called “dried distiller's grain and solubles” or DDGS.

There have been proposals to use DDGS, or stover, or a combination ofthe two, as fuel to produce process heat for the ethanol manufacturingprocess. In some proposals, the material is used to fuel a cogenerationplant that produces (a) electricity to power equipment employed at theethanol manufacturing facility and (b) steam for use as the heatingmedium in stages of the ethanol manufacturing process that require heat.A cogeneration plant is a substantial capital expense.

With respect to the use of stover as a fuel, there are some drawbacks.The stover has to be gathered from the field and baled for moreefficient handling and transportation and then transported to theethanol manufacturing facility, all of which entails expense andconsumes fuel. Moreover, when stover is removed from the field, thisdeprives the field of the benefits arising when stover is left in thefield (soil building and erosion prevention).

As noted above, corn intended for subsequent processing into ethanol isconventionally harvested with a combine that both picks and shells thecorn. Seed corn and sweet corn are harvested by another type ofself-propelled equipment known as an ear corn harvester which picks thecorn but does not shell it. In the case of seed corn, the ear corn,after harvesting, is stored and dried and then shelled by a piece ofequipment separate and discrete from the earn corn harvester. Thisprotects the corn kernels that are to be used as seed, from damage thatcan occur when shelling is performed by a combine. Damaged corn kernelsare unsuitable for use as seed.

In rural corn-growing areas, during the first half of the twentiethcentury and earlier, corn cobs were used as kindling for coal-burning,home heating furnaces and hot water heaters. In some rural areas, duringthe depression in the 1930's and during the war years in the 1940's, earcorn was used as a substitute for coal in home heating furnaces.

Stanfield U.S. Pat. No. 4,139,952 discloses a procedure in which ears ofseed corn are dried by heat generated at an incinerator and then shelledto produce (a) kernels of seed corn and (b) corn cobs that are employedas fuel for the incinerator.

It is possible to produce ethanol from cellulose contained in stover.However, it is currently much more difficult to produce ethanol fromstover than from shelled corn, and substantially more expensive. At thepresent time production of ethanol from stover is not economicallyattractive.

SUMMARY OF THE INVENTION

In the present invention, corn cobs are used as fuel in the ethanolmanufacturing process. In the farm field, the combine is replaced by anear corn harvester. Quantities of ear corn harvested by a plurality ofear corn harvesters are transported to a central shelling stationlocated at or next to, or otherwise associated with, the ethanolmanufacturing facility. At the central shelling station, the ear corn isshelled to separate the corn kernels from the corn cobs, the shelledcorn is conveyed to the first stage of the ethanol manufacturingprocess, and the corn cobs are combusted to produce heat for the process

Compared to conventional practice, energy is conserved in the harvestingof the corn, in the shelling of the corn and in the combustion of fuelto provide heat for the ethanol manufacturing process. Operating costsare reduced at the farm, at the central shelling station and at theethanol manufacturing facility.

Other features and advantages are inherent in the invention claimed anddisclosed or will become apparent to those skilled in the art from thefollowing detailed description, much of which is a projection, inconjunction with the accompanying flow diagram.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a flow diagram illustrating an embodiment of a method inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the flow diagram of FIG. 1, indicated generally at 11 (andcontained within dashed lines in FIG. 1) is an ethanol manufacturingfacility which performs a multi-stage process for converting shelledcorn into ethanol. Some of the processing stages require heat which isprovided by combusting fuel at a combustion chamber 20 located withinfacility 11.

A central shelling station 10 is located at or next to (i.e., physicallyassociated with) ethanol manufacturing facility 11, or is otherwiseassociated with facility 11. Ear corn harvested from a number of farmfields by a plurality of ear corn harvesters 25 is transported tocentral shelling station 10 where the ear corn is shelled to separatethe corn kernels from the corn cobs. As used herein, the term “centralshelling station” refers to a stationary piece of shelling equipmentthat shells ear corn harvested by a plurality of ear corn harvesters.

The shelled corn from central shelling station 10 is conveyed to thefirst stage 12 of ethanol manufacturing facility 11 where the shelledcorn is milled. The shelled corn may be directly conveyed to first stage12, or it may be temporarily stored in silos or the like for subsequentconveyance to first stage 12.

Corn cobs from shelling station 10 are conveyed to combustion chamber 20where the cobs are combusted to provide some or all of the heat forthose stages of the process that require heat. The cobs from shellingstation 10 may be directly conveyed to combustion chamber 20, or theymay be held at storage sites adjacent shelling station 10 or adjacentcombustion chamber 20 or at other storage sites at facility 11, forsubsequent conveyance to and/or introduction into combustion chamber 20.

At first processing stage 12, the shelled corn is ground into a finepowder called meal, and the meal is then conducted to a liquefactionstage 13 where water and an initial enzyme (alpha amylase) are added andmixed with the meal. The resulting mixture is then passed throughcookers where heat is applied to liquefy the starch in the meal. Thecookers comprise an initial stage at 13, where the mixture is cooked ata relatively high temperature (e.g., 100°-150° C.) to reduce bacterialevels in the mixture, followed by a holding stage 14 where the mixtureis maintained at a lower temperature (e.g. 95° C.), with additionalheat, if required.

From holding stage 14, the cooked mixture is conducted to a sugarformation stage 15 where additional (secondary) enzyme is added (e.g.,glucoamylase), to convert the starch in the mixture to fermentablesugars (e.g., dextrose). The resulting mixture of sugar and residualmaterial is then conducted to a fermentation stage 16 where yeast isadded to ferment the sugars into ethanol. During fermentation, largequantities of carbon dioxide gas (CO₂) are emitted, and this additionalreaction product can be captured, compressed and sold commercially.

Fermentation may be continuous wherein the sugar-containing mixtureflows through a series of fermenting sub-stages until the sugars arefully fermented; or fermentation may be conducted as a batch process inwhich the sugar-containing mixture is held in one fermenting stage foran extended period of time (e.g., 48 hours) until fermentation iscomplete.

The fermented mixture or mash product at fermentation stage 16 comprises10% alcohol plus residual, non-fermentable solids from the corn and fromthe yeast cells. The mash from fermentation stage 16 is then directed toa distillation stage 17 where heat is applied to distill the ethanolfrom the mash. Typically, the mash is pumped through a continuous flow,multi-stage, distillation system where the ethanol is removed from thesolids and separated from the water in the mash to produce 96% strengthethanol which is conducted to a dehydration stage 18 where the remainingwater is removed to give 200 proof, anhydrous (no water) ethanol.

The residual mash from distillation stage 17 is called stillage whichmay be conducted to a dryer 22 where heat is applied to remove water andproduce a dried product called distillers dried grain and solubles(DDGS) which has value as an animal feed. Undried stillage may also beemployed as an animal feed.

The anhydrous ethanol from dehydration stage 18 is conducted to adenaturing stage 19 where 2-5% gasoline is added to make the ethanolunfit for human consumption. The resulting product is composed of 95-98%ethanol which is then transported to a blending facility 21, typicallyat a location remote from ethanol manufacturing facility 11. At blendingfacility 21, the ethanol is mixed with additional gasoline inappropriate proportions that enable the ethanol to be used either as anadditive (e.g., a blend with 10% ethanol) or as a fuel (e.g., 85%ethanol).

The heat for liquefaction and holding stages 13, 14, for distillationstage 17 and for dryer 22 is provided by combusting corn cobs fromshelling station 10. Combustion typically occurs at combustion chamber20, but combustion may also be performed at an auxiliary combustionchamber, e.g., a combustion chamber associated with dryer 22. Theheating medium for a given heating location may be steam or heated air.The largest part of the total heat requirements for the process is thatemployed at distillation stage 17. Preferably, combustion chamber 20 islocated adjacent distillation stage 17.

The ash produced by the combustion of the corn cobs contains mineralswhich have some value as fertilizer and can be given away for spreadingon a farm field 23 within an economically transportable distance frommanufacturing facility 11. Otherwise, the ash is transported to a nearbyland fill 24.

Depending upon the quantity of corn cobs produced at the centralshelling station, the corn cobs used as fuel replace some or all of thenatural gas conventionally used as fuel for the ethanol manufacturingprocess. Because the corn cobs are a byproduct of the shelling operationconducted at central shelling station 10, they constitute fuel obtainedfree of charge. In contrast, natural gas is relatively expensive, sothat the replacement of natural gas by corn cobs produces substantialcost savings.

Moreover, corn cobs are a renewable fuel source obtained by replantingthe corn field from which the cobs were harvested (or an equivalentfield); natural gas is not renewable. In addition, the carbon dioxideemitted into the atmosphere by the combustion of corn cobs is offset bythe carbon dioxide absorbed from the atmosphere during the growing ofthe corn; there is no such offset for the carbon dioxide emitted intothe atmosphere by the combustion of natural gas.

Central shelling station 10 shells ear corn from a multitude of cornfields where the ear corn was previously conventionally shelled bycombines that can be replaced by ear corn harvesters when a centralshelling station is employed. The combination of ear corn harvesters anda central shelling station provides several advantages compared tocombines.

A typical ear corn harvester can pick six or seven rows of corn in onepass; some models can pick ten rows. (The picking operation is similarto that performed by a combine.) The ears of corn are husked, the husks(and any tramp stover elements) are returned to the field, and the earcorn is conveyed, in one model, to a tiltable dump hopper at the rear ofthe ear corn harvester. The dump hopper is equipped with a hydrauliclift which is operated to tilt the dump hopper about a high tilt axis tounload the hopper quickly into a truck or semi-trailer having relativelyhigh sides. The quick-unload feature minimizes the time spent by theharvester on activities other than harvesting (i.e., “down time”).

In another model, the ear corn is conveyed into a dump cart that runsalongside the ear corn harvester. The dump cart is pulled by a tractorand has the same kind of dump hopper with hydraulic lift described inthe preceding paragraph, to facilitate quick unloading.

An ear corn harvester can make a harvesting pass through a corn field ata faster speed than a combine because the speed at which a combine canpick corn is restrained by the rate at which the combine can shell theear corn the combine has picked. An ear corn harvester has no suchrestraint and can harvest at cruising speeds, e.g., in the range 18-21miles per hour. Comparing an ear corn harvester and a combine, each ofwhich can pick the same number of corn rows in a single pass, the earcorn harvester, due to its faster picking speed, will pick a givenacreage in a shorter time period than a combine picking the sameacreage. Expressed another way, an ear corn harvester can pick a givenacreage in the same amount of time as a combine that can pick more rowsof corn in a single pass.

The discussion in the following part of this paragraph assumes asituation in which ear corn harvesters and combines each pick the samenumber of corn rows in a single pass. Given the acreage of corn requiredto satisfy the annual demand of an ethanol manufacturing facility, thatacreage can be harvested during a given harvest season with fewer earcorn harvesters than the number of combines required to harvest the sameacreage. As a result, there is less total capital expense when ear cornharvesters are employed, even assuming that an ear corn harvester and acombine cost the same. (Actually, a combine costs more.) There is alsoless total operational expense, even assuming that the operationalexpense for a single ear corn harvester is the same as that for a singlecombine; and there is less total labor expense. Moreover, there is alsoless total fuel consumed in operating the smaller number of ear cornharvesters, even assuming that a single one of each of the two types ofequipment consumes the same amount of fuel during a given period ofoperation.

In actuality, an ear corn harvester consumes less fuel than a combineharvesting the same number of corn rows in a single pass. This isbecause, unlike the combine, the ear corn harvester does not consume thefuel required for operating shelling equipment and does not consume thefuel required for transporting the weight of the shelling equipment upand down rows in the corn field. (It is assumed that the weight of theother equipment on the ear corn harvester and combine (e.g. corn pickingequipment and corn storage and unloading structure) weigh substantiallythe same; any substantial difference in the weight of this otherequipment could result in a difference in the amount of fuel consumed.)Although the ear corn harvester operates at a faster speed than thecombine when picking corn, the combine runs for a longer period of timeto pick the same acreage, so that there is probably no substantialdifference in the amount of fuel consumed due to picking corn atdifferent speeds. Some of the energy saving attributable to the absenceof a shelling function on an ear corn harvester is offset downstream inshelling ear corn at the central shelling station. However, the shellingequipment at the central shelling station is stationary, and unlike acombine, no energy is expended transporting that shelling equipment upand down corn rows.

As noted above, there is a situation where the number of ear cornharvesters employed is the same as the number of combines. In thissituation, the combine is large enough to pick more rows in a singlepass than the speedier ear corn harvester; but the ear corn harvesterstill has a cost advantage over the combine. More particularly, eachlarge combine costs more than an ear corn harvester, and the number ofpieces of equipment required to harvest the acreage in question issubstantial. Accordingly, there will be a substantial saving in totalcapital expense when employing ear corn harvesters in lieu of largecombines; and there should be less operational expense and less fuelconsumed when one employs the ear corn harvesters. Labor expense will bethe same.

Ear corn harvesters of the types described above are available from thefollowing source: Oxbo International Corporation, 7525 Byron Road,Byron, N.Y., 1422-0100. Brochures describing the ear corn harvesters canbe obtained from that company's website: www.oxbocorp.com; and thedisclosures therein are incorporated herein by reference.

The use of a single, central shelling station, instead of shelling witha multitude of combines at each of a multitude of individual cornfields, conserves energy in a number of ways. Each of the multitude ofcombines employed to shell corn in conventional procedures has its owninternal combustion engine which runs on a petroleum-based liquid fuel.A central shelling station would employ the efficiencies of scale toshell the same amount of corn with less fuel, assuming the shellingequipment at the central shelling station was powered by an internalcombustion engine. However, the central shelling station would mostlikely be powered by an electric motor driven by electricity from powerlines. The electricity obtained from power lines in the corn-growingmidwest is typically generated at a power plant fueled by coal ornuclear fuel. Natural gas or petroleum-based liquid fuels are generallynot employed and are thus conserved when a central shelling station isemployed.

Moreover, even if the central shelling station were powered by aninternal combustion engine, the combination of ear corn harvester andcentral shelling station would still consume less fuel than the use of acombine to both pick and shell corn. More particularly, and as notedabove, when shelling with a combine, fuel is consumed not only tooperate the shelling equipment on the combine, but also to move theweight attributable to the shelling equipment up and down the corn rows,and this occurs in each of the multitude of corn fields supplying cornto the ethanol manufacturing plant. In contrast, with a central shellingstation, the shelling equipment is stationary, and the fuel consumed inmoving the shelling equipment in a combine up and down corn rows isconserved. (This is in addition to the fuel that would be conserved at acentral shelling station due to efficiencies of scale).

The capital investment in the shelling equipment at a central shellingstation will be substantially less than the cumulative capitalinvestment attributable to the shelling equipment in a multitude ofcombines shelling the same quantity of corn. This is because theshelling equipment in a combine must be large enough to shell, duringthe relatively short period of time in a harvest season, all of the cornpicked by the combine in that season (a mere few weeks). In contrast,the shelling equipment at the central shelling station need only belarge enough to shell the same quantity of corn over a year-long period.The central shelling station is, of course, scaled up to handle thequantity of corn previously shelled by a multitude of combines. However,even if one assumes conservatively that the shelling equipment in thecombines will be operated for a period of two months, the shellingequipment at a central shelling station operated all year long need onlyhave one-sixth the cumulative shelling capacity of the multitude ofcombines replaced by the central shelling station. Moreover, aspreviously noted, the central shelling station conserves thepetroleum-based fuel consumed by the combines to move the weight of theshelling equipment thereon up and down rows in the cornfields.Conservation of fuel in this manner can be quite substantial because theweight of the shelling equipment moved up and down corn rows by thecombines has six times the shelling capacity of the stationary shellingequipment at the central shelling station.

Of course, all of the above-noted reductions in the consumption ofpetroleum-based fuel also reduce costs. Moreover, as previously noted,the central shelling station will most likely be powered by electricity.This presents an opportunity for reducing operating expenses bymaximizing the operation of the shelling equipment during late night andearly morning hours when electricity rates are lower.

Factors which offset some of the cost savings and fuel conservationdescribed above are the cost of transporting to the central shellingstation that part of the ear corn attributable to the weight and/orvolume of the corn cobs, and the fuel consumed in doing so. These areincremental items of transportation cost and fuel consumption. The costof transporting that part of the ear corn attributable to the cornkernels, and the fuel consumed in doing so, were already part of thetransportation cost and fuel consumption when shelled corn from combineswas transported to the ethanol manufacturing facility.

Another factor partially offsetting the cost savings described abovearises when a farmer raises both corn and soy beans and needs a combineto harvest the soy beans. A farmer who has replaced the combine with anear corn harvester would need to contract out the combining of soybeans.

Tabulated below is a summary of the effect of the present invention oncosts and on the consumption of natural gas or petroleum-based fuel.

Effect on Consumption of natural gas Feature of the Present orpetroleum- Effect on Invention based fuel Costs Use of corn cobs as fuelin Decreased Decreased the ethanol manufacturing process Shelling at acentral shelling Decreased Decreased station instead of shelling with amultitude of combines Picking corn with an ear corn Decreased Decreasedharvester instead of with a combine Transporting ear corn to theIncreased Increased central shelling station

Because of the efficiencies of scale and other factors discussed above,the cost of shelling ear corn at a central shelling station should besubstantially less than the cost of employing a multitude of combines toperform the shelling at each of a multitude of corn fields. The savingsobtained by eliminating the cost of shelling with a combine at the cornfield goes initially to the farmer. The lesser cost of shelling at thecentral shelling station is borne by the ethanol processor, at leastinitially. However, the cost of shelling at a central station can bedistributed proportionally among the farmers, when computing the priceto be paid to the farmers for ear corn, and because the cost of shellingat the central shelling station is less than the cumulative cost ofshelling at a multitude of farm fields, the farmers would still come outahead.

In preferred embodiments of the present invention, the central shellingstation is located either at the site of the ethanol manufacturingfacility or adjacent thereto. In each such instance, the centralshelling station is deemed to be physically associated with the ethanolmanufacturing facility. The central shelling station (CSS) can bephysically removed from the ethanol manufacturing facility (EMF) wherebyshelled corn and corn cobs have to be transported by truck or rail fromthe CSS to the EMF, but the two locations can be otherwise associated inaccordance with a broader sense of the present invention, so long as atransportation expense criterion described below is met.

There are two stages of transportation when the central shelling stationis not physically associated with the ethanol manufacturing facility:(1) transportation of ear corn to the central shelling station; and (2)transportation of shelled corn and corn cobs from the central shellingstation to the ethanol manufacturing facility. Part of the cost of thefirst transportation stage is attributable to the cost of transportingthe unseparated corn cobs in the ear corn, and part of the cost of thesecond transportation stage is attributable to the cost of transportingthe corn cobs from which the shelled corn has been separated. When (a)the combined costs from transportation stages (1) and (2), attributableto transporting the corn cobs, is less than (b) the cost savingsobtained by replacing natural gas with corn cobs as the fuel forproducing process heat at the ethanol manufacturing facility, thecentral shelling station is deemed to be associated with the ethanolmanufacturing facility in accordance with the broader sense of thepresent invention.

Further with respect to a physically associated central shellingstation, in many instances an ethanol manufacturing facility is locatedin a rural area where it is surrounded by farms (a) that can supply aphysically associated central shelling station with ear corn and (b)that are sufficiently close so that the expense of transporting ear cornto the physically associated central shelling station becomes aninsignificant factor.

Preferably, the central shelling station is operated to provide shelledcorn to the ethanol manufacturing facility on a just-in-time basis inaccordance with the requirements of that facility. This minimizes theneed for shelled corn storage space which is typically in the form ofreinforced concrete silos, or the like. It also minimizes the need forcorn cob storage space, the character of which need be only rudimentary,e.g., three sides of containment walls with one open side for access bymaterial handling equipment, such as a front end loader, and anoverhanging roof to protect the cobs from rain or snow.

To the extent that storage space is required, it will be for ear corn,and the storage requirements for ear corn are not as elaborate (orexpensive) as the storage requirements for shelled corn. On the otherhand, the footprint and volume of the storage space for a given quantityof ear corn is substantially greater than the foot print and volume ofthe storage requirements for the shelled corn derived from that quantityof ear corn. However, one does not need a large inventory of ear corn tooperate the central shelling station on a just-in-time basis. One needonly have (1) a sufficient supply of ear corn in storage to allowoperation of the central shelling station at a rate dictated by thedemands of the ethanol manufacturing facility together with (2) regular,periodic deliveries of ear corn to replenish the inventory of ear corndepleted by the operation of the central shelling station.

Ideally, ear corn is delivered to the central shelling station on ajust-in-time basis; this would minimize the need for ear corn storagespace there. In such a situation, the bulk of the ear corn required bythe central shelling station over a year's time would be stored at farmsor at an intermediate storage location which performs a function for earcorn akin to that performed by a grain elevator for shelled corn.

There are benefits to storing corn as ear corn rather than as shelledcorn. As noted above, the storage facility for ear corn is lesselaborate than the storage facility for shelled corn which must be fullyenclosed and protected from the elements. In contrast, ear corn storedon the farm (or at an intermediate storage facility) is stored in a corncrib (or equivalent storage facility) having a floor, a roof and sidewalls with openings to allow ambient air to circulate through the storedear corn. Ear corn dries naturally when stored in a corn crib or thelike. Depending upon the initial moisture content, drying can besubstantial during the first 30 to 60 days of storage in a corn crib orthe like. In contrast, shelled corn does not sufficiently dry naturallyin its storage facility; instead, shelled corn must be artificiallydried with a dryer that burns fuel to provide the drying heat.

More particularly, with respect to shelled corn and ear corn eachharvested from a corn field at the same moisture content, and eachstored in its respective storage facility for the same period of time,the ear corn will dry naturally while stored in a corn crib or the like;but shelled corn must be artificially dried to attain the same reducedmoisture content as that attained by the ear corn during storage (e.g.,18% moisture or less).

Shelled corn is dried by a dryer that typically burns natural gas sothat the drying process consumes an energy source that is expensive andnon-renewable. If ear corn were to be shelled at the central shellingstation after being dried artificially at a dryer that burns corn cobsfrom the sheller (as is done with seed corn in Stansfield U.S. Pat. No.4,139,952, discussed above in the “Background” section), such aprocedure would deprive the ethanol manufacturing process of aninexpensive, renewable fuel, and the corn cobs would have to be replacedthere with natural gas. Thus, storing ear corn in a corn crib or thelike to reduce the moisture content of the ear corn, before shelling ata central shelling station, conserves energy and reduces expense. Asused herein, the term “corn crib or the like” refers to a storagefacility for ear corn that allows air to circulate through the ear cornto dry the ear corn naturally. At one time, there was a rat problemassociated with the storage of ear corn, but contemporary expedients fordealing with that problem have it under control.

As noted above, ideally, ear corn is delivered to the central shellingstation on a just-in-time basis. In a less-preferred embodiment, ayear's supply of ear corn is delivered to the central shelling stationover a relatively short period of time, substantially less than a year.If the central shelling station is sized to shell ear corn over a twelvemonth period, then there must be sufficient storage space to accommodatethe ear corn surplus until it can be shelled.

An alternative solution to the aforementioned scenario would be toincrease the size of the central shelling station so that it could shella year's supply of ear corn in substantially less than a year. Thiswould reduce the storage space requirements for ear corn, but it wouldincrease the storage space requirements for shelled corn and corn cobs.This alternative would also increase the capital expense for theshelling equipment at the central shelling station; but it would noteliminate all of the savings in operating expenses or all of thereduction in energy consumption obtained by employing the combination ofear corn harvesters and central shelling station, all of which isdiscussed in detail above. For example the stationary central shellingstation still conserves the fuel consumed by combines moving the weightof their shelling equipment up and down corn rows, no matter what thesize of the central shelling station.

The foregoing detailed description is a projection. It has been givenfor clearness of understanding only, and no unnecessary limitationsshould be understood therefrom, as modifications will be obvious tothose skilled in the art.

1. A method for producing ethanol at an ethanol manufacturing facilitythat receives, as feed materials, corn and corn cobs characterized byhaving previously been subjected to processing that has been performedupstream of the ethanol manufacturing facility and that has comprised:providing a plurality of farm fields that supply corn and cobs as feedmaterials to the ethanol manufacturing facility; at each of said farmfields, employing harvesting equipment to pick corn plant materialsincluding ear corn comprising corn and corn cobs as components;separating said ear corn components after said picking step; deliveringcorn plant material comprising cobs, from a plurality of farm fields, toa location that is downstream of said farm fields and remote from thefarms where the cobs are harvested; said upstream processing includingat least one of the following expedients (a)-(c), (a) delivering saidcorn plant material comprising cobs to said downstream location withoutconsuming cobs to dry ear corn there, (b) performing said upstreamprocessing without consuming cobs to dry concurrently corn and cobs thatare received at an ethanol manufacturing facility, and (c) performingsaid upstream processing without consuming corn, unfit for seed, to drycobs that are received at an ethanol manufacturing facility; and whereinsaid method comprises: providing, at said location, an ethanolmanufacturing facility that makes ethanol from corn and that is remotefrom the farms that supply said ethanol manufacturing facility with feedmaterials; receiving, at said ethanol manufacturing facility, from aplurality of farm fields, feed materials comprising corn and cobscharacterized by having undergone said previous upstream processing; theproportion of cobs in the feed materials being greater than theproportion therein of stover ingredients other than cobs; the ratio ofcobs to said other stover ingredients, in the feed materials, beinggreater than the ratio of cobs to said other stover ingredients in thecorn plant; the ratio of cobs to corn in the feed materials beinggreater than the ratio of stover ingredients, other than cobs, to cornin said feed materials; chemically processing a corn plant ingredientinto ethanol; using heat in said processing; and employing corn plantmaterial comprising cobs as a source of fuel for the heat used in saidprocessing; the proportion of cobs, in the corn plant material employedas said source of fuel, being (a) greater than the proportion of cobs inthe stover of the corn plant and (b) greater than the proportion ofstover ingredients other than cobs in the material employed as saidsource of fuel.
 2. A method as recited in claim 1 wherein said upstreamprocessing has comprised: harvesting both said corn and said cobs in asingle pass without slowing the harvesting of the corn compared to amethod that harvests the same quantity of corn without harvesting cobs;and said method comprises employing corn plant material, harvested bysaid harvesting equipment in a single pass, as feed material at anethanol manufacturing facility.
 3. A method as recited in claim 1wherein: both (a) the feed materials received at the ethanolmanufacturing facility and (b) the corn plant material employed as saidsource of fuel comprise cobs without other stover ingredients.
 4. Amethod as recited in claim 1 wherein: said picking step is performed byan ear corn harvester; said separating step is performed at a centralseparating station that receives ear corn from a plurality of said farmfields and delivers corn and cobs to said ethanol manufacturingfacility; and said upstream processing has been performed withoutcarrying stalks on said harvesting equipment after said picking step. 5.A method as recited in claim 1 wherein: the totality of the ethanol madefrom corn plant material, harvested at a field that supplies saidethanol manufacturing facility, is made at said ethanol manufacturingfacility that is remote from the farms that supply it.
 6. A method asrecited in claim 1 wherein: said upstream processing has been performedwithout carrying cobs per se on the harvesting equipment after thepicking step.
 7. A method as recited in claim 1 wherein: said upstreamprocessing has been performed without consuming cobs to dry cornupstream of the ethanol manufacturing facility; and the corn from a farmfield that supplies both cobs and corn to an ethanol manufacturingfacility is received at the same ethanol manufacturing facility as thecobs from which that corn was separated.
 8. A method as recited in claim1 and comprising: providing a storage site downstream of the farm fieldsthat supply the ethanol manufacturing facility with feed materials;delivering corn plant material comprising cobs to said storage site,after said separating step; and storing cobs at said storage site beforethe cobs are employed as a source of fuel at the ethanol manufacturingfacility; the proportion of cobs in the corn plant material delivered tosaid storage site being (a) greater than the proportion of cobs in thestover of the corn plant and (b) greater than the proportion, in saiddelivered material, of stover ingredients other than cobs.
 9. A methodas recited in claim 1 wherein: the corn plant material delivered to saiddownstream location comprises a plurality of corn plant ingredients. 10.A method for producing ethanol at an ethanol manufacturing facility thatreceives, as feed material, corn plant material comprising cobscharacterized by having previously been subjected to processing that hasbeen performed upstream of the ethanol manufacturing facility and thathas comprised: providing a plurality of farm fields that supply corn andcobs as feed materials to an ethanol manufacturing facility; at each ofsaid farm fields, employing harvesting equipment to pick corn plantmaterials including ear corn comprising corn and corn cobs ascomponents; separating said ear corn components after said picking step;delivering corn plant material comprising cobs, from a plurality of farmfields, to a location that is downstream of said farm fields and remotefrom the farms where the cobs are harvested, and that is physicallyassociated with an ethanol manufacturing facility that receives corn asa feed material; said upstream processing including at least one of thefollowing expedients (a)-(c), (a) delivering said corn plant materialcomprising cobs to said downstream location without consuming cobs todry ear corn there, (b) performing said upstream processing withoutconsuming cobs to dry concurrently corn and cobs that are received at anethanol manufacturing facility, and (c) performing said upstreamprocessing without consuming corn, unfit for seed, to dry cobs that arereceived at an ethanol manufacturing facility; and wherein said methodcomprises: providing an ethanol manufacturing facility with which saidlocation is physically associated and that is remote from farms thatsupply said ethanol manufacturing facility with feed material; receivingat said location, as feed material for an ethanol manufacturing facilitywith which said location is physically associated, from a plurality offarm fields, corn plant material comprising cobs characterized by havingundergone said previous upstream processing; the proportion of cobs insaid feed material being greater than the proportion therein of stoveringredients other than cobs; the ratio of cobs to said other stoveringredients, in said feed material, being greater than the ratio of cobsto said other stover ingredients in the corn plant; in the whole of thefeed materials received at an ethanol manufacturing facility with whichsaid location is physically associated, the ratio of cobs to corn isgreater than the ratio of stover ingredients, other than cobs, to corn;chemically processing a corn plant ingredient into ethanol at an ethanolmanufacturing facility with which said location is physicallyassociated; using heat in said processing; and employing corn plantmaterial comprising cobs as a source of fuel for the heat used in saidprocessing; the proportion of cobs, in the corn plant material employedas said source of fuel, being (a) greater than the proportion of cobs inthe stover of the corn plant and (b) greater than the proportion ofstover ingredients other than cobs in the material employed as saidsource of fuel; said heat being used in the processing performed at anethanol manufacturing facility with which said location is physicallyassociated and that receives corn as a feed material.
 11. A method asrecited in claim 1 or 10, wherein said expedient is (a).
 12. A method asrecited in claim 1 or 10, wherein said expedient is (b).
 13. A method asrecited in claim 1 or 10, wherein said expedient is (c).
 14. A method asrecited in claim 1 or 10, wherein said expedient is (a) together with(c) or (b) together with (c).